The long-term goal of this Program-Project is to provide new information about the structure and function of plasma lipoproteins and to utilize existing and new knowledge for the formulation of a general theory of lipid transport processes. The conceptual framework of the entire program is based on the view that apolipoproteins are the most probable determinants of the structural stability and functional specificity of lipoproteins. This Program-Project consists of four projects and a Core Laboratory. Project 1 (Isolation and characterization of human serum apolipoproteins and lipoprotein families) and Project 2 (Studies of apolipoprotein B and its lipoproteins in human plasma) are primarily concerned with the chemistry of lipoproteins. Project 3 (Regulation of plasma lipoprotein production by the liver) is centered around studies on the processes regulating the formation of apolipoproteins and lipoproteins, whereas Project 5 (Studies on turkey plasma and arterial lipoproteins) is concerned with the chemical and immunologic characterization of turkey plasma and arterial lipoproteins, and the interaction between plasma lipoproteins and arterial wall in this animal species. The purpose of the Core Laboratory is to provide amino acid analyzer, gas-liquid chromatography, ultracentrifugation, and immunoassay services for the entire Program-Project.